Storage device, storage control method, and computer-readable recording medium storing storage control program

Abstract

A storage device comprising a storage including a first pool area providing a physical area in units of first chunks of first size, and a second pool area providing a physical area in units of second chunks of second size smaller than the first size, and a controller. The controller counts a first count value indicating a number of first divided areas in which data is stored from among a plurality of the first divided areas obtained by dividing, by the second size, a virtual volume that has the first chunk allocated only to an area in which data is stored. In a case where a ratio of the first count value to a number of the first chunks allocated to the virtual volume is equal to or less than a first threshold, allocate the second chunk instead of the first chunk to the virtual volume.

What is claimed is: 
     
         1 . A storage device comprising:
 a storage in which a first pool area that provides a physical storage area in units of first chunks of a first size, and a second pool area that provides a physical storage area in units of second chunks of a second size smaller than the first size are set; and   a controller including a processor configured to   count a first count value that indicates a number of first divided areas in which data is stored from among a plurality of the first divided areas obtained by dividing, for the each second size, a virtual volume that has the first chunk allocated only to an area in which data is stored from the first pool area, and   in a case where a ratio or an increase amount of the first count value to a number of the first chunks allocated to the virtual volume is equal to or less than a first threshold,
 allocate the second chunk from the second pool area instead of the first chunk to the virtual volume and 
 move the data of the first chunk allocated to the virtual volume to the second chunk allocated to the virtual volume. 
   
     
     
         2 . The storage device according to  claim 1 , wherein
 the first size is a multiple of the second size.   
     
     
         3 . The storage device according to  claim 1 , wherein,
 in the storage, a third pool area that provides a physical storage area in units of third chunks of a third size larger than the first size is further set, and   the processor is further configured to   count a second count value that indicates a number of second divided areas each has the first chunks allocated entirely to the second divided area, and a third count value that indicates a number of second divided areas each has the first chunk allocated only to part of the second divided area, from among a plurality of the second divided areas obtained by dividing the virtual volume for each third size,   in a case where a ratio of the second count value to a total value of the second count value and the third count value is equal to or greater than a second threshold,
 allocate the third chunk from the third pool area instead of the first chunk to the virtual volume, and 
 move the data of the first chunk allocated to the virtual volume to the third chunk allocated to the virtual volume. 
   
     
     
         4 . The storage device according to  claim 3 , wherein
 the third size is a multiple of the first size.   
     
     
         5 . A storage control method performed by a computer comprising a storage in which a first pool area that provides a physical storage area in units of first chunks of a first size, and a second pool area that provides a physical storage area in units of second chunks of a second size smaller than the first size are set, the method comprising steps of;
 counting a first count value that indicates a number of first divided areas in which data is stored from among a plurality of the first divided areas obtained by dividing, for the each second size, a virtual volume that has the first chunk allocated only to an area in which data is stored from the first pool area, and   in a case where a ratio or an increase amount of the first count value to a number of the first chunks allocated to the virtual volume is equal to or less than a first threshold,
 allocating the second chunk from the second pool area instead of the first chunk to the virtual volume and 
 moving the data of the first chunk allocated to the virtual volume to the second chunk allocated to the virtual volume. 
   
     
     
         6 . A non-transitory computer readable recording medium storing a storage control program that causes a computer, comprising a storage in which a first pool area that provides a physical storage area in units of first chunks of a first size, and a second pool area that provides a physical storage area in units of second chunks of a second size smaller than the first size are set, to perform steps of;
 counting a first count value that indicates a number of first divided areas in which data is stored from among a plurality of the first divided areas obtained by dividing, for the each second size, a virtual volume that has the first chunk allocated only to an area in which data is stored from the first pool area, and   in a case where a ratio or an increase amount of the first count value to a number of the first chunks allocated to the virtual volume is equal to or less than a first threshold,
 allocating the second chunk from the second pool area instead of the first chunk to the virtual volume and 
 moving the data of the first chunk allocated to the virtual volume to the second chunk allocated to the virtual volume.